Answer:
The surface area is divided by 4.
Step-by-step explanation:
Surface area of a sphere is 4πr².
When the diameter is 28 the radius is 14. So: 4π(14)² = 784π
If you cut the diameter in half you get 14. The radius is now 7.
4π(7)² = 196π.
784/4 = 196 so divided by 4.
A) The longest horizontal distance is reached at 45 degrees angle. This is true for any projectile launch.
B) First, calculate fligth time (using the vertical motion) and then calculate the horizontal movement.
Flight time = 2* ascendent time
ascendent time => final vertical velocity, Vy, = 0
sin(45) = Voy / Vo => Voy = Vosin(45) = 25.5 m/s * (√2) / 2 = 18.03 m/s
Vy = Voy - gt = 0 => Voy = gt = t = Voy / g
Use g = 10 m/s^ (it is an aproximation, because the actual value is about 9.81 m/s^2 depending on the latitud)
t = 18.03 m/s / 10 m/s^2 = 1.83 s
This is the ascendant time going upward.
The flight time is 2*1.83 = 3.66 s
Horizontal motion
Horizontal velocity = Vx = constant = Vox = Vo*cos(45) = 18.03 m/s
Vx = x / t => x = Vx*t
Horizontal distance = xmax = 18.03m/s*3.66 s = 65.99 m
c) The time the ballon will be in the air was calculated in the part B, it is 18.03 s
It's not possible nothing but 1 times 5 is the only thing that multiplies to 5 and 1+5 doesn't equal 4
